REVENUE FROM CONTRACTS WITH CUSTOMERS AND LEASE INCOME - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2020 |
Dec. 31, 2019 |
|
| Disaggregation of Revenue [Line Items] | |||
| Contract assets | $ 103 | $ 103 | $ 117 |
| Contract liabilities | 57 | 57 | 52 |
| Revenue from contracts with customers recognized | 11 | 21 | |
| Unregulated Distributed Generation | |||
| Disaggregation of Revenue [Line Items] | |||
| Contract assets | 41 | 41 | 40 |
| Contract liabilities | 26 | $ 26 | 28 |
| GEORGIA POWER CO | |||
| Disaggregation of Revenue [Line Items] | |||
| Revenue, performance obligation, description of timing | Georgia Power had contract assets primarily related to unregulated service agreements, where payment is contingent on project completion, and fixed retail customer bill programs, where the payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over a one-year contract term. Contract liabilities for Georgia Power relate to cash collections recognized in advance of revenue for certain unregulated service agreements. Alabama Power had contract liabilities for outstanding performance obligations primarily related to extended service agreements. | ||
| Contract assets | 54 | $ 54 | 69 |
| Contract liabilities | $ 23 | $ 23 | $ 13 |